Will the following do what you want:
f[u_,v_]:=Sin[u+v]
mydata = Flatten[Table[{u, v, f[u,v]} // N, {u, 0, 2 Pi}, {v, 0, 2Pi}],
1]; mydata // MatrixForm
Note that MatrixForm is a wrapper function that affects output display
in the frontend
If you need to export the data as a CSV table use the following
(insert the correct path for where you want the file to be exported to)
Export["/Users/brian/Desktop/mydata.csv", mydata, "CSV"]
Or if you want to export to a tab seprated table use the following
Export["/Users/brian/Desktop/mydata.dat", mydata, "Table"]
Hope this helps,
Cheers,
Brian